The present invention is related to seedbed conditioning tillage tools and more specifically to vertical tillage tools.
To prepare a seed bed for planting, many types of tilling tools have been developed. Currently, the most commonly used tilling tools include cultivators and combination tillage units that include soil engaging components (i.e., disks, tillage tines, etc.) that completely sweep (i.e., smears) an entire tillage floor to turn over and loosen all of the top soil that covers a field. For example, some tillage systems may include two rows of disks arranged such that the disks essentially completely turn over all top soil in a field. To this end, the disks are designed to have characteristics and are juxtaposed with respect to each other and a travel direction such that all of the soil is turned. Typically, to turn all soil via disks, each disk is relatively deeply concave and is inclined at a relatively steep angle with respect to the travel direction. In addition to loosening top soil, these types of tilling tools also have an advantageous leveling effect on soil as they are pulled through a field. Here, level soil is important to minimize bounce of planter assemblies that are subsequently used in a field so that seed depth can be relatively accurately controlled. Unfortunately, while these types of tilling tools loosen or till top soil well, these types of tools tend to compact under soil (i.e., soil below the top soil) as portions of the soil engaging components smear across the under soil during travel. More specifically, when a deep dish disk is inclined relatively steeply to a travel direction, the backside of the disk tends to smear and compress soil therebelow. When under soil is smeared, the density of the under soil increases and root growth is inhibited.
To reduce the smearing effect, rotary spike harrows have been developed that, as the label implies, include rotary spike toothed members that are mounted to a harrow axle and that generally rotate about a horizontal harrow axis substantially normal to or on a slight incline (e.g., 15°-35°) with respect to a travel direction. Here, the spikes of each toothed member penetrate soil by being driven substantially vertically downward and disrupt the soil as the spike angle within the soil changes during member rotation. The end result is tillage with less smearing effect (slight smearing still results in some applications).
While rotary spike harrows reduce smearing/soil compaction, unfortunately these types of tilling tools have several shortcomings. First, rotary spike toothed harrows usually include a relatively large number of toothed members arranged on an axle so that the weight of the tilling implement is distributed over a large number of member teeth and the spikes do not, under typical soil conditions, penetrate the soil being tilled to a desired level during a single pass. Second, rotary spike toothed harrows do not level soil to the same extent as other types of tilling tools during a single pass through a field. Here, the shortcomings of the spike toothed harrows can be overcome by increasing the number of passes through a field (e.g., 3 passes instead of a single pass). Obviously additional passes require additional time and thus are not desirable.
Thus, it would be advantageous to have a tilling tool or assembly that could adequately till a field in a single pass while minimizing smearing and soil compaction.